The present invention concerns a hydraulic valve clearance compensator for an internal combustion engine. The compensator has a housing shaped essentially like an upside-down cup with a flat base. The housing slides up and down inside a central bore. The housing accommodates two concentric hollow cylinders sealed off from each other and separated by an axially resilient compression spring. In the wall of the housing there is at least one inlet that supplies lubricant to one cylinder. Between the inlet and the cylinders is a check valve that allows lubricant to flow through the inlet into the cylinder and prevents it from flowing out.
A valve clearance compensation device of this type is known from the German Patent Publication No. OS 3,150,083. A flexible rubber seal constitutes a check valve that seals off a reservoir of hydraulic fluid. The valve tappet is supplied with enough fluid to ensure normal operation even when the engine has been inoperative for some time because the valve prevents fluid from leaking out of the reservoir. The tappet is supplied through a bore with lubricant from the engine's lubricating system. The bores in the cylinder head make a mechanism of this type very expensive to manufacture.